With the development of Internet technology, the networks are of ever increasing scales, various network services emerge and so do advanced multimedia systems. Because real-time services like multimedia service are generally sensitive to network transmission delay, delay jitter and other characteristics, when there is File Transfer Protocol (FTP) service with high burst possibility or Hyper Text Transfer Protocol (HTTP) service with image files, transmission performance of real-time services will be greatly affected; for another, multimedia services in communication networks can occupy large amount of bandwidths, so that key services asking the network for transmission quality may not be transmitted reliably.
Based on the above-mentioned requirement, various techniques providing Quality of Service (QoS) guarantee for service transmission emerge as the times require. To meet the Qos demand of transmission, Internet Engineering Task Force (IETF) has put forward some service models and mechanisms. At present, utilizing Diff-Serv model in core of the network is widely accepted by the prior art thereof. Diff-Serv model adopts the measure of setting priority levels to guarantee transmission QoS, although this measure can increase utility rate of bandwidth resource, specific application effect is hard to predict due to lack of corresponding maintenance and management message interaction.
Therefore, an independent bearer control layer is introduced into backbone network Diff-Serv model to manage resources of the bearer network. For instance, to prompt application of Diff-Serv model, in the QoS Backbone (Qbone) experimental networks driven by IETF and some manufacturers as well as research organizations, bearer network resource managers are used to implement resource and topology management in bearer network, namely to manage topology resources and coordinate QoS capabilities of Diff-Serve model areas. This kind of Diff-Serve manner that implements said resource management is right the Diff-Serve model with independent bearer control layer.
In a Diff-Serve model with independent bearer control layer, resource management rules and network topology structure of bearer network connection nodes are configured inside bearer network resource manager, and bearer, network resource manager takes charge of allocating bandwidth resources on the user's request of service bandwidth application. Request of service bandwidth application and result of the user as well as path information allocated by bearer network resource managers for the service are transferred through signaling between each bearer network resource manager.
When processing the user's request of service bandwidth application, bearer control layer determines path of the user service, and bearer network resource manager notifies edge routers, namely connection nodes of the bearer network, to transfer the service stream according to the specified path.
To meet the message transmission requirements between bearer network resource managers, Internet2 specifically defines corresponding Bandwidth Broker (BB), Call Agent (CA) or Connection Management (CM) for each Diff-Serve model management domain as bearer network resource managers; therein said bandwidth broker takes charges in processing the requests of bandwidth application from user hosts or service servers or network maintainers, wherein the bandwidth broker determines whether to permit the user's bandwidth application according to resource reservation status of current network and configuration policy as well as Service Level Agreement (SLA); said call agent acts as a service server which is used to access the user's call to the communication network; said connection manager is used for service layer controlling bearer network layer according to service requirements.
But there are some problems in the above-described Diff-Serv model that is based on bandwidth broker and with independent bearer control layer, for example, Simple Inter-domain Bandwidth Broker Signaling (SIBBS) is adopted between bandwidth brokers to implement the resource request, wherein this signaling is only used between bandwidth brokers and there is no resource synchronization mechanism between bandwidth brokers, namely that resource requests are transmitted through SIBBS directly without the procedure of session establishment or maintenance either without message interaction mechanism used for maintenance and management.
At present, there is no mature technical solution in the prior art to transfer request of service bandwidth application and result of the user as well as path information allocated for service request by bearer network resource manager, etc.